1. Field of the Invention
The present invention relates to a display device, and more particularly to an interconnection of a display device including an OLED.
2. Discussion of the Related Art
In a multimedia age, it is required for a display device to be finer and larger and to express colors close to natural colors. There are limits to a CRT (Cathode Ray Tube) which is a conventional general display device. An LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), an OLED (Organic Light Emitting Diode), a projection TV (Television) and the like are developing at a high speed to be widely used in a field of high-definition images.
Among the above-mentioned display devices, the OLED is a self light emitting display device, which has advantages such as a large viewing angle, excellent contrast and fast response time. Generally, an organic EL device has a structure in which an anode is formed on a substrate, and a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer and a cathode are sequentially formed on the anode. Further, when a voltage is applied between the anode and the cathode, holes injected from the anode move to the light emitting layer through the hole transporting layer. Meanwhile, electrons are injected into the light emitting layer from the cathode through the electron transporting layer. In a region of the light emitting layer, carriers are recombined to produce excitons. The excitons move from an excited state to a ground state. Accordingly, fluorescent molecules of the light emitting layer emit light to form an image.
However, the above-mentioned conventional display devices such as an OLED have the following problems.
It is impossible to stably manufacture a display device such as an OLED on general glass and plastic in the recent technology. For example, since the OLED has an advantage capable of being bent or crooked, it is manufactured using a high priced special substrate. Accordingly, when the substrate including the OLED is used as a display device in an electronic product and the like, there are the following problems.
FIG. 1 illustrates a plan view showing an interconnection structure of a substrate including an OLED in the prior art. An OLED device 100 is formed on a substrate 110 in FIG. 1. In this case, although the OLED device including four pixels is schematically depicted in FIG. 1, the OLED device is generally formed of more pixels to transfer image information or text information. In this case, the OLED device is used as a display device of an application product 130 such as an air conditioner. Thus, the substrate 110 with the OLED device 100 is attached to one surface of the application product 130. Further, a transparent conductive material 120 is formed on the substrate 110 to connect the respective pixels to electrode lines 140 of the application product 130. That is, the transparent conductive material 120 serves to transfer current, light emitting signals and the like to the respective pixels of the OLED device 100.
In this case, the transparent conductive material 120 formed on the substrate 110 is formed of ITO (Indium-Tin-Oxide). Further, as shown in FIG. 1, since the area of the transparent conductive material 120 is larger than the area of the OLED device 100 in the substrate 110, there is a problem of spending the manufacturing cost for a high priced substrate. That is, only a portion, for example, a central portion of the high priced substrate is used to manufacture a light emitting device and the other portion thereof is wasted. That is, since it is impossible to stably manufacture a display device on general glass and plastic in the recent technology, when it is impossible to form a display device on a substrate having the same area as a small area of an application product, the cost is wasted.